Light emitting device and manufacture method thereof

ABSTRACT

A manufacture method of a light emitting device is provided. Firstly, at least one circuit board is provided. A plurality of light emitting packages, a first undetermined power input end and a second undetermined power input end are disposed at the circuit board. The light emitting packages are electrically connected to the first undetermined power input end and the second undetermined power input end. Each of the first undetermined power input end and the second undetermined power input end has at least two first pads. The first pads of each of the first undetermined power input end and the second undetermined power input end are electrically isolated from each other. Next, the first undetermined power input end is selected to be a power input region for inputting an external power signal. Then, the first pads of the second undetermined power input end are electrically connected to each other.

This application claims the benefit of Taiwan application Serial No.96122195, filed on Jun. 20, 2007, the subject matter of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a light emitting device and amanufacture method thereof, and more particularly to a light emittingdevice with a light source disposed on a circuit board and themanufacture method thereof.

2. Description of the Related Art

If a light emitting diode (LED) element is used as a light source in abacklight module, the LED element is normally soldered on a circuitboard to form a lighting bar. The lighting bar is further incorporatedwith other optical elements and is disposed in the backlight module. Thebacklight module is classified into an edge type backlight module and adirect type backlight module according to a light-emitting surface ofthe light source.

Let an edge type backlight module be taken for example. For theconvenience of the assembly and operation of the edge type backlightmodule, power lines for inputting an external power are disposed at thesame side of the edge type backlight module. As a result, circuit boardssoldered with LED elements need to have two different forms. Althoughaccording to the design of a linked board diagram, the circuit boards ofdifferent forms can be formed on the same linked board. However, thenumber of the circuit boards formed on the linked board is limited to beeven, hence increasing the manufacture cost.

In addition, if LED elements comprise chips of three colors, forexample, red, green and blue, the arrangement of the chips in the samekind of the LED elements is the same. Referring to FIG. 1, a perspectiveof a direct type backlight module is shown. The direct type backlightmodule 100 comprises a plurality of circuit boards 110. Each of thecircuit boards 110 has a plurality of LED elements 111 in the same form.The LED elements 111 are used as light sources of the direct typebacklight module 100.

As the LED elements 111 herein are in the same form, the arrangement ofthe chips of three colors in the LED elements 111 is the same. That is,the arrangement of the chips is a red chip 112, a green chip 113 and ablue chip 114 in order. As illustrated in FIG. 1, under sucharrangement, a particular color tends to be over-concentrated in acertain direction.

Thus, when the direct type backlight module 100 is in use, several colorbands are formed by over-concentrated colors, hence affecting displayqualities. Although the above problem can be avoided through the designof different circuit boards, the circuit boards on the same linked boardare still subjected to the above limitation that the number of thecircuit boards has to be even.

SUMMARY OF THE INVENTION

The invention is directed to a light emitting device and a manufacturemethod thereof. Two undetermined power input ends are disposed on acircuit board, so that the application of the light emitting devicehaving such circuit board is more flexible.

According to a first aspect of the present invention, a manufacturemethod of a light emitting device is provided. Firstly, at least onecircuit board is provided. A plurality of light emitting packages, afirst undetermined power input end and a second undetermined power inputend are disposed on the circuit board. The light emitting packages areelectrically connected to the first undetermined power input end and thesecond undetermined power input end. Each of the first undeterminedpower input end and the second undetermined power input end has at leasttwo first pads electrically isolated from each other. Next, the firstundetermined power input end is selected to be a power input region forinputting an external power signal. Then, the first pads of the secondundetermined power input end are electrically connected to each other

According to a second aspect of the present invention, a light emittingdevice is provided. The light emitting device is disposed in a displayapparatus. The light emitting device comprises a plurality of lightemitting packages and at least one circuit board. The light emittingpackages are disposed on the circuit board. The circuit board comprisesa first undetermined power input end and a second undetermined powerinput end. The first undetermined power input end and the secondundetermined power input end are respectively disposed at two ends ofthe circuit board. The first undetermined power input end and the secondundetermined power input end are electrically connected to the lightemitting packages. Each of the first undetermined power input end andthe second undetermined power input end has at least two first pads. Thefirst undetermined power input end is a power input region. The firstpads of the second undetermined power input end are electricallyconnected to each other.

The invention will become apparent from the following detaileddescription of the preferred but non-limiting embodiments. The followingdescription is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (Related Art) is a perspective of a direct type backlight module;

FIG. 2 is a flowchart of a manufacture method of a light emitting deviceaccording to the invention;

FIGS. 3A˜3C illustrate processes of the manufacture method of the lightemitting device of FIG. 2;

FIG. 4 is a flowchart of a manufacture method of a light emitting deviceaccording to a second embodiment of the invention; and

FIG. 5 is a perspective of the light emitting device according to thesecond embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

Referring to both FIG. 2 and FIGS. 3A˜3C. FIG. 2 is a flowchart of amanufacture method of a light emitting device according to theinvention. FIGS. 3A˜3C illustrate processes of the manufacture method ofthe light emitting device of FIG. 2.

Firstly, as illustrated in FIG. 2 and FIG. 3A, proceeds to step 301, acircuit board 230 is provided. A plurality of light emitting packages210, a first undetermined power input end 231 and a second undeterminedpower input end 232 are disposed on the circuit board 230. The firstundetermined power input end 231 and the second undetermined power inputend 232 are respectively disposed at two ends of the circuit board 230.The light emitting packages 210 are electrically connected to the firstundetermined power input end 231 and the second undetermined power inputend 232. The first undetermined power input end 231 has two first pads231 a and 231 b, and the second undetermined power input end 232 has twofirst pads 232 a and 232 b. The first pads 231 a and 231 b areelectrically isolated from each other, and the first pads 232 a and 232b are electrically isolated from each other.

Next, as illustrated in FIG. 2 and FIG. 3B, proceeds to step 303, thefirst undetermined power input end 231 is selected to be a power inputregion 233 for inputting an external power signal. In the presentembodiment of the invention, the first undetermined power input end 231is selected to be the power input region 233. However, in step 303, thesecond undetermined power input end 232 also can be selected to be thepower input region 233. The selection in step 303 is determinedaccording to a user's requirement.

Then, as illustrated in FIG. 2 and FIG. 3C, the manufacture methodproceeds to step 305, the first pads 232 a and 232 b of the secondundetermined power input end 232 are electrically connected to eachother. In the present embodiment of the invention, as the firstundetermined power input end 231 is selected to be the power inputregion 233 in step 303, the first pads 232 a and 232 b of the secondundetermined power input end 232 are electrically connected to eachother in step 305. Thus, the light emitting device 200 of the presentembodiment of the invention is formed after the above steps, and theexternal power signal is inputted to each of the light emitting packages210 through the first pads 231 a and 231 b of the power input region233.

According to the light emitting device and the manufacture methodthereof disclosed in the present embodiment of the invention, the firstundetermined power input end and the second undetermined power input endare respectively disposed on the two ends of the circuit board, so thata user, according to his (or her) requirement, can select one of thefirst undetermined power input end and the second undetermined powerinput end to be the power input region for inputting the external powersignal. The first pads of the other one of the first undetermined powerinput end and the second undetermined power input end are thenelectrically connected to each other so as to form a loop on the circuitboard. Therefore, the application of the light emitting device is moreflexible.

In the present embodiment of the invention, as illustrated in FIG. 3C,each of the light emitting packages 210 has a light emitting chip 211,such as a light emitting diode (LED) chip. The circuit board 230 has along-side direction D1 and a short-side direction D2. The first pads ofthe first undetermined power input end and the second undetermined powerinput end of the present embodiment of the invention are arranged alongthe short-side direction. That is, as illustrated in FIG. 3C, the firstpads 231 a and 231 b of the first undetermined power input end 231 arearranged along the short-side direction D2, and the first pads 232 a and232 b of the second undetermined power input end 232 are also arrangedalong the short-side direction D2.

In addition, in the present embodiment of the invention, the number ofthe first pads of each of the first undetermined power input end and thesecond undetermined power input end is twice as the kinds of the lightemitting chips 211. As the light emitting packages 210 has one kind oflight emitting chip 211 only, the first undetermined power input end 231has two first pads 231 a and 231 b. Furthermore, the second undeterminedpower input end 232 also has two first pads 232 a and 232 b.

Second Embodiment

Referring to FIG. 4, a flowchart of a manufacture method of a lightemitting device according to a second embodiment of the invention isshown. Compared with the flowchart of FIG. 2, the flowchart of FIG. 4further comprises steps 401, 403 and 409. Steps 405 and 407 of FIG. 4are the same with step 303 and step 305 of FIG. 2 and it does not saymore than what is needed.

Also referring to FIG. 5, a perspective of the light emitting deviceaccording to the second embodiment of the invention is shown. Forsimplification, the same elements are selectively designated in FIG. 5.The present embodiment of the invention differs from the firstembodiment in that the light emitting device 200′ has a plurality ofcircuit boards 230 a, 230 b, 230 c and 230 d, and each of the lightemitting packages 210 of each of the circuit boards 230 a, 230 b, 230 cand 230 d has the light emitting chips of three colors, for example, redlight emitting chips 211R, green light emitting chips 211G and bluelight emitting chips 211B.

As illustrated in FIG. 4 and FIG. 5, proceeds to step 401, an internalcircuit 235′ is disposed at each of the circuit boards 230 a, 230 b, 230c and 230 d, and a plurality of first pads is disposed at each of thefirst undetermined power input ends 231′ and each of the secondundetermined power input ends 232′ along the short-side direction D2′ ofeach of the circuit boards 230 a, 230 b, 230 c and 230 d. The internalcircuit 235′ has a plurality of second pads 237′ electrically connectedto the light emitting packages 210′. In the present embodiment of theinvention, the number of the first pads of each of the firstundetermined power input end and the second undetermined power input endis twice as the kinds of the light emitting chips. In the presentembodiment of the invention, the light emitting chips have three kinds,so the number of the first pads of each of the first undetermined powerinput end and the second undetermined power input end is six.

Next, the manufacture method proceeds to step 403, a plurality of lightemitting packages 210′ is disposed on the circuit boards 230 a, 230 b,230 c and 230 d along the long-side direction D1′ of each of the circuitboards 230 a, 230 b, 230 c and 230 d, respectively, so that the lightemitting chips of three colors (211R, 211G and 211B) disposed in each ofthe light emitting packages 210′ are arranged along the short-sidedirection D2′ according to a predetermined order. The light emittingpackages 210′ are electrically connected to the second pads 237′. Afterstep 403, step 405 and step 407 are performed sequentially. As disclosedabove, step 405 and step 407 of FIG. 4 are the same with step 303 andstep 305 of FIG. 2 and it does not say more than what is needed.

In the present embodiment of the invention, in step 405, the firstundetermined power input ends 231′ of the circuit boards 230 a and 230 dare selected to be the power input regions 233′, and the secondundetermined power input ends 232′ of the circuit boards 230 b and 230 care selected to be the power input regions 233′. Thus, in step 407, thefirst pads of the second undetermined power input ends 232′ of thecircuit boards 230 a and 230 d are electrically connected to each other,and the first pads of the first undetermined power input ends 231′ ofthe circuit boards 230 b and 230 c are electrically connected to eachother. Therefore, through the design of the first undetermined powerinput end and the second undetermined power input end of each of thecircuit boards, the arrangement of the circuit boards is determinedaccording to a user's requirement.

In the present embodiment of the invention, in step 407, the first padsof the second undetermined power input ends 232′ of the circuit boards230 a and 230 d are electrically connected to each other by at least onesolder 242′, and so are the first pads of the first undetermined powerinput ends 231′ of the circuit boards 230 b and 230 c. However, forexample, 0 Ohm resistors also can be used to electrically connect thefirst pads of the first undetermined power input ends 231′ or the secondundetermined power input ends 232′.

Then, the manufacture method proceeds to step 409, a connector 240′ isdisposed to electrically connect the first pads of the power inputregions 233′ for inputting an external power signal. Alternatively, instep 409 of the present embodiment of the invention, at least one solderwire (not illustrated) is disposed to electrically connect the firstpads of the power input regions 233′ for inputting the external powersignal.

Thus, the light emitting device 200′ which can be disposed in a displayapparatus (not illustrated) is used for providing a direct typebacklight light source.

In step 405 of the present embodiment of the invention, the firstundetermined power input ends 231′ of the circuit boards 230 a and 230 dare selected to be the power input regions 233′ and the secondundetermined power input ends 232′ of the circuit boards 230 b and 230 care selected to be the power input regions 233′. However, the aboveselection of the power input region is not limited. As a result, theapplication of the circuit boards is more flexible, and the circuitboards can be arranged alternately in the light emitting device 200′because of the design of the first undetermined power input end and thesecond undetermined power input end for reducing the over-concentrationof a particular color in a certain direction.

According to the light emitting device and the manufacture methodthereof disclosed in the above embodiments of the invention, through thedesign of the first undetermined power input end and the secondundetermined power input end of the circuit boards, the application ofthe light emitting device having such circuit boards is more flexible.In addition, the number of the circuit boards disposed at a linked boardis not limited to be even for further saving the manufacture cost of thelight emitting device.

While the invention has been described by way of example and in terms ofa preferred embodiment, it is to be understood that the invention is notlimited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

1. A light emitting device disposed in a display apparatus, comprising:a plurality of light emitting packages; and at least one circuit boardcomprising a first undetermined power input end and a secondundetermined power input end, wherein the light emitting packages aredisposed on the circuit board, the first undetermined power input endand the second undetermined power input end are respectively disposed attwo ends of the circuit board, the first undetermined power input endand the second undetermined power input end are electrically connectedto the light emitting packages, each of the first undetermined powerinput end and the second undetermined power input end has at least twofirst pads, the first undetermined power input end is a power inputregion, and the first pads of the second undetermined power input endare electrically connected to each other.
 2. The light emitting deviceaccording to claim 1, wherein the light emitting device furthercomprises: a connector electrically connected to the first pads of thepower input region.
 3. The light emitting device according to claim 1,wherein the light emitting device further comprises: at least one solderwire disposed at the power input region and electrically connected tothe first pads of the power input region.
 4. The light emitting deviceaccording to claim 1, wherein the light emitting device furthercomprises: at least one solder or at least one resistor electricallyconnected the first pads of the second undetermined power input end,wherein the resistance of the resistor is 0 Ohm.
 5. The light emittingdevice according to claim 1, wherein the circuit board furthercomprises: an internal circuit electrically connected to the firstundetermined power input end and the second undetermined power inputend; and a plurality of second pads disposed in the internal circuit andelectrically connected to the light emitting packages.
 6. The lightemitting device according to claim 1, wherein the light emitting devicecomprises a plurality of circuit boards, each of which has a long-sidedirection and a short-side direction, and the circuit boards arearranged along the short-side direction.
 7. The light emitting deviceaccording to claim 1, wherein the circuit board has a long-sidedirection and a short-side direction, each of the light emittingpackages has at least one light emitting chip, each of the firstundetermined power input end and the second undetermined power input endhas a plurality of first pads arranged along the short-side direction,and the number of the first pads of each of the first undetermined powerinput end and the second undetermined power input end of the circuitboard is twice as the kinds of the light emitting chips.
 8. The lightemitting device according to claim 7, wherein the light emittingpackages each of which has a plurality of light emitting chips of threecolors are arranged along the long-side direction and the light emittingchips of three colors are arranged along the short-side directionaccording to a predetermined order.
 9. The light emitting deviceaccording to claim 7, wherein the light emitting chip is a lightemitting diode (LED) chip.